This invention involves a disposable protective liner for gratings such as are commonly found in paint spray booths of the type typically employed in automotive assembly plants. However, it is to be understood that the present invention is equally adaptable to protective liners for gratings in any other field of application where the grating must remain porous to airflow in an environment where the grating is exposed to a gradual build-up of a contaminant coating as a result of airborne contaminants or spillage and the like.
In paint spray booths, it is common to have the flooring in the form of a grating or grid-like structure which permits airflow to pass through it so that airborne overspray paint can be directed to a wet type of air scrubber or other type of filter system to remove the paint from the air. The structure of the grating inevitably receives a gradual accumulation of the airborne paint, with the result that the grating openings are gradually reduced in size to the point that adequate airflow therethrough is no longer possible. This problem requires the periodic removal and cleaning of the grating by a paint stripping process that necessarily imposes a time, space and cost penalty on the operator of the facility.
Accordingly, it is the primary object of the present invention to provide an improved means of maintaining adequate airflow through a grating type of structure which is exposed to a gradual build-up of difficult to remove contaminants on its surfaces.
Two prior art patents show covers or mats for wire screens but intended to act as spacers rather than disposable contamination shields for the underlying screen to maintain air flow therethrough. In Cobb, U.S. Pat. No. 4,023,530, a molded cover for a hen-house cage floor is designed to interfit with the screen to prevent contact between the rusted screen and the hens or eggs, or to prevent formation of rust in the first instance. Cobb is not concerned with the problem of diminished air flow through the screen, in that the excrement may be readily removed (see col. 1, lines 22-27). Nor does Cobb have to replace his covers due to any build-up thereon. Similarly, the patent to Keen, U.S. No. 3,641,983, shows a spacer mat for a screen-like poultry cage floor. Keen's mat does not have openings corresponding with the screen opening spacing, and such mat is intended to be washable rather than disposable.